The result of your conversion between megajoule and grain/cubic foot appears here
To convert between Megajoule and Grain/cubic Foot you have to do the following:
First divide 1000000 / ((0.45359237/16)*(192/175)/480)/((0.0037854118/231)*1728) = 436995725.88008511
Then multiply the amount of Megajoule you want to convert to Grain/cubic Foot, use the chart below to guide you.
Symbol: MJ
No description
Symbol: gr/ft³
No description